External validation of multivariable prediction models: a systematic review of methodological conduct and reporting

Before considering whether to use a multivariable (diagnostic or prognostic) prediction model, it is essential that its performance be evaluated in data that were not used to develop the model (referred to as external validation). We critically appraised the methodological conduct and reporting of external validation studies of multivariable prediction models.We conducted a systematic review of articles describing some form of external...